Kevin Mandia's Armadin raises $255.5M Series B at a $2.5B+ valuation
Kevin Mandia's Armadin raised a $255.5 million Series B at a valuation above $2.5 billion, co-led by Andreessen Horowitz and Accel, seven months after launching with $189.9 million in combined seed and Series A funding — $445 million in total. The startup replaces periodic human-led penetration testing with always-on autonomous agent swarms that chain vulnerabilities together to simulate attacks before real adversaries can.
Armadin, the AI-native offensive security company led by Mandiant founder Kevin Mandia, has raised $255.5 million in Series B funding co-led by Andreessen Horowitz and Accel, valuing it at more than $2.5 billion. New investors Bain Capital Ventures and Redpoint joined, and existing backers 8VC, Ballistic Ventures, Google Ventures, In-Q-Tel, Kleiner Perkins and Menlo Ventures returned. The round, announced on October 1, brings total funding to $445 million.
The raise comes just seven months after Armadin emerged from stealth on March 10 with $189.9 million in combined seed and Series A funding led by Accel, which it called the largest such round in cybersecurity history. The company says it is already running agentic attack campaigns in production for Fortune 500 companies and government customers.
Armadin's pitch is that frontier AI has shrunk the time between a vulnerability's disclosure and a working exploit so much that periodic penetration tests can't keep up, while scanners score each finding in isolation. Its platform deploys a swarm of specialized AI agents that reason like a skilled adversary across external assets, cloud, identity, internal networks and applications, chaining individually low-severity weaknesses into validated kill chains, from unauthenticated code execution at the perimeter through lateral movement to full cloud compromise. Security teams see each attack path and its blast radius and can close it before a real attacker uses it.
"Offense is uniquely advantaged right now," Mandia said. "AI lets an attacker find and chain weaknesses faster than any human team can respond." Mandia leads the company with co-founders Travis Lanham, Evan Peña and David Slater, who previously built Google security products and led Mandiant's red team. Armadin will use the funds to scale its platform, research, training and go-to-market efforts.